黑蚱蝉鸣声的结构和音色特征

本文对北京、河北和福建等地黑蚱蝉(Cryptotympana atrata Fabricius)的三种鸣声进行了分析,并对发声机理进行了讨论。 黑蚱蝉野外的自然鸣声具有基本相同的结构层次,都由重复频率为43—49Hz的节奏组成,每个节奏含有4个单音节,每个单音节含有3个脉冲群,每个脉冲群含有若干个脉冲。但是音色有明显的差异,即分别为单音色、双音色和具有高幅低频声的复合声。黑蚱蝉室内的惊鸣声和自鸣声,虽然音色有一定的变化,但仍保持自然鸣声的结构层次。鸣声的结构层次明显取决于发声膜的结构特征,这表明具有种类的特性。音色的差异性不仅与调音、扩音结构的功能有关,而且可能与发声膜的力学性质和发声的原初过程有关,即可能具有地区性和种下差异。 这些结果可为蝉类发声机制和有害昆虫声引诱的声学模型的研究提供依据。

CHARACTERISTICS OF THE STRUCTURE AND TIMBRE OF SONGS OF THE BLACK CICADA CRYPTOTYMPANA ATRATA FABRICIUS

Three kinds of songs of the black cicada Cryptotympana atrata Fabricius distributed in Beijing, Hebei and Fujian Provinces are analyzed. The natural calling songs in the field of different places have basically the same structural levels; they consist of rhythms with repetition frequency of 43-49 Hz, each rhythm with four syllables, each syllable with three pulse-groups and each pulse group with several pulses. But the timbres present obvious difference; they differentiate into single timbre, dual timbre and complex timbre with a low frequency sound of high amplitude. The protest songs and the free songs in the room still retain the structural level of the natural songs though the timbres present some changes. It seems most likely that the structural levels of the songs depend on the structural characteristics of the tymbals which show specificity of the species. The differences of the timbres are related not only to the functions of the sound regulators and the resonant cavities, but also to the mechanical pro-perty of the tymbals and the original process of sound production. These differences may be present in the black cicadas from different geographical regions. The results of the present work may provide informations for further study of the mechanism of sound production in cicadas and deriving acoustic model for luring the injurious species.